This invention relates to an exhaust system for motorcycles and more particularly to an improved compact exhaust system and a cooperating engine mounting arrangement for motorcycles.
In many types of motorcycles, the engine is mounted with its crankshaft extending transversely to the longitudinal axis of the motorcycle. As a result, one or more cylinders of the engine may have rearwardly facing exhaust ports. When the engine has rearwardly facing exhaust ports, there arise certain difficulties in connection with the routing of the exhaust system from the exhaust ports to the atmosphere. These problems may be particularly acute when the engine is of the V type and has both forwardly and rearwardly facing cylinder banks.
It is the common practice to employ a suspension system for the rear wheel that includes a trailing arm having a forward pivotal axis to the frame. With such an arrangement, it is necessary for the exhaust system to clear the pivot axis of the rear suspension arm. This can be done by moving the pivot axis rearwardly and passing the exhaust pipe between the engine crankcase and the pivot axis. Such an arrangement, however, unnecessarily lengthens the wheel base of the motorcycle. Alternatively, it is possible to pass the exhaust pipe between the pivot axis and the rear wheel. When this is done, however, there must be sufficient clearance allowed for suspension movement and servicing becomes difficult. Furthermore, the wheel base may nevertheless be extended due to the necessity of providing clearance between the exhaust system, rear suspension and the rear wheel.
It is, therefore, a principal object of this invention to provide an improved exhaust system for a motorcycle.
It is another object of the invention to provide a motorcycle exhaust system that permits a compact arrangement, does not lengthen wheel base and yet facilitates servicing of the motorcycle.
It is a still further object of this invention to provide an improved exhaust system for a motorcycle having a V type engine.
In motorcycles, it is also desirable to suspend the engine from the frame in such a way that loadings on the frame can be equalized. The construction of the motorcycle and the clearance for the various components can be reduced if the engine mounting points are reduced. If only a single engine mounting point is used for one portion of the engine, it is desirable to insure that this mounting point is carried by the frame in such a way that uneven loadings on the frame are minimized.
It is, therefore, a further object of this invention to provide an improved and simplified mounting arrangement for a motorcycle engine.